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The pecan nut casebearer, a tiny worm that can nearly wipe out a pecan crop if in high population and not controlled, is at the stage where growers need to decide if they will spray, said Joe Janak, Victoria County extension agent.

Typically, the worm infests pecan trees between May 1-12 each year for the first generation, with a second generation about 42 days later.

Casebearer eggs and even nut entries by the worms were found as of Tuesday in several orchards and it is time to spray to control them now through this week, possibly until Sunday. Pecan tree owners can best control the pest by spraying an insecticide into the tree foliage coating the tiny nutlets to provide protection.

Janak has set out pecan casebearer insect traps with local growers and as normal, activity varies from location to location. In three out of five orchard sites, casebearer populations are high enough and timely to provide control applications immediately through Sunday.

In the other two orchards, casebearer activity has been light and no control is recommended at this time, but control may possibly be needed by Sunday or later or maybe even not at all, Janak said.

Extension philosophy on spraying to control any pest, including the pecan nut casebearer, is to use the integrated pest management method whereby growers monitor pest levels, crop production potential, beneficials, economics and finally, if necessary, use the least harmful pesticide.

If spraying is needed, the best advice for homeowners is: Spinosad, Bacillus thuringiensis or malathion. Other labeled insecticides include Chlorpyrifos, Cypermethrin, Cyfluthrin, Esfenvalerate, Diflubenuron, Methoxyfenozide, Phosmet, Tebufenozide, Zeta-cypermethrin, Gamma-cyhalothrin, Lambdacyhalothrin, and Carbaryl.

Biological control options include Spinosad, Tebufenozide, and Bacillus thuringiensis .

For greater effectiveness with an insecticide, remember to buffer the water with a commercial buffering product or vinegar if you have alkaline water.

“ I’m always asked what level of vinegar to use,” Janak said. “Really, I don’t know as it varies on the alkalinity of your water.”

Russell Ham, manager of Surface Water Drinking Plant in Victoria, said the city water pH is normally about 7.6 – 7.8 pH. The optimum pH of water used to spray insecticides is between 5.5 and 6.5. This is best adjusted by using a buffering agent, but vinegar or similar acid can be used without delay after mixing.

Zinc, a nutrient, should also be mixed with the insecticide and sprayed on the leaves now. In fact, for proper management, at least two to three applications of zinc should have already been applied within the past two months.

Pecan tree varieties that are susceptible to scab, a common pecan fungus, should have fungicides applied.